On 12/3/2011 11:41 AM, Vladimir Serbinenko wrote:
/* nthibr.c - tests whether an MS Windows system partition is hibernated */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2007,2008,2009,2011 Free Software Foundation, Inc.
*
* GRUB is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* GRUB is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GRUB. If not, see<http://www.gnu.org/licenses/>.
*/
#include<grub/types.h>
#include<grub/mm.h>
#include<grub/disk.h>
#include<grub/file.h>
#include<grub/misc.h>
#include<grub/dl.h>
#include<grub/extcmd.h>
#include<grub/lib/arg.h>
#include<grub/err.h>
#include<grub/i18n.h>
GRUB_MOD_LICENSE("GPLv3+");
/* Define this 'empty' array to let the '-h' and '-u' switches be processed */
static const struct grub_arg_option options[] = {
{0, 0, 0, 0, 0, 0}
};
No need for empty array. passing 0 instead of this array works.
I have tried it both ways. For some reason, passing the empty array
works, but passing a null pointer doesn't.
That is, when I try the latter, the options '-u' and '-h' are treated as
regular arguments to the command.
static grub_err_t
grub_cmd_nthibr (grub_extcmd_context_t ctxt __attribute__ ((unused)),
int argc, char **args)
{
grub_err_t status = GRUB_ERR_NONE;
char *partition_name, *hibr_file_path = 0, hibr_file_magic[5];
grub_size_t name_length;
grub_ssize_t magic_size;
grub_disk_t partition;
grub_file_t hibr_file = 0;
/* Check argument count */
if (!argc)
{
status = grub_error (GRUB_ERR_BAD_ARGUMENT,
N_("too few arguments specified"));
goto exit;
}
else if (argc> 1)
{
status = grub_error (GRUB_ERR_BAD_ARGUMENT,
N_("too many arguments specified"));
goto exit;
}
partition_name = args[0];
name_length = grub_strlen (partition_name);
/* Check if partition specifier 'looks right' */
if (partition_name[0] != '(' || partition_name[name_length - 1] != ')')
{
status = grub_error (GRUB_ERR_BAD_FILENAME,
N_("invalid partition specifier"));
goto exit;
}
I would recommend adding '(' and ')' if none found rather than giving error.
/* Check if partition actually exists */
partition_name[name_length - 1] = '\0';
partition = grub_disk_open (partition_name + 1);
if (!partition)
{
status = grub_error (GRUB_ERR_UNKNOWN_DEVICE,
N_("partition not found"));
No need to run grub_error here. grub_disk_open already sets grub_errno
and grub_errmsg. Just status = grub_errno is enough.
goto exit;
}
else
{
grub_disk_close (partition);
partition_name[name_length - 1] = ')';
}
No need for 'else' clause (goto already takes care of it)
/* Build path to 'hiberfil.sys' */
hibr_file_path = grub_malloc (grub_strlen (partition_name)
+ grub_strlen ("/hiberfil.sys") + 1);
if (!hibr_file_path)
{
status = grub_error (GRUB_ERR_OUT_OF_MEMORY,
N_("out of memory"));
goto exit;
}
else
{
grub_strcpy (hibr_file_path, partition_name);
grub_strcat (hibr_file_path, "/hiberfil.sys");
}
Same here (no need for grub_error and else)
/* Try to open 'hiberfil.sys' */
hibr_file = grub_file_open (hibr_file_path);
if (!hibr_file)
{
status = grub_error (GRUB_ERR_FILE_NOT_FOUND,
N_("'hiberfil.sys' not found"));
ditto
goto exit;
}
/* Try to read magic number of 'hiberfil.sys' */
magic_size = sizeof (hibr_file_magic) - 1;
grub_memset (hibr_file_magic, 0, sizeof (hibr_file_magic));
if (grub_file_read (hibr_file, hibr_file_magic, magic_size)< magic_size)
{
status = grub_error (GRUB_ERR_BAD_FILE_TYPE,
N_("'hiberfil.sys' too small"));
you need to conditionalize call to grub_error. if (!grub_errno) ...
since incomplete read may indicate an FS problem in which case you want
the original error message to remain.
goto exit;
}
/* Return SUCCESS if magic indicates file is active; else return FAILURE */
if (!grub_strncasecmp ("hibr", hibr_file_magic, magic_size))
grub_puts (N_("The system is hibernated."));
else
{
grub_puts (N_("The system is NOT hibernated."));
status = GRUB_ERR_TEST_FAILURE;
}
We also do grub_error (GRUB_ERR_TEST_FAILURE, "false");
exit:
/* Ensure unmanaged resources are cleaned up */
if (hibr_file_path)
grub_free (hibr_file_path);
grub_free already checks for not-NULL pointers.
if (hibr_file)
grub_file_close (hibr_file);
return status;
You can eliminate status and the need of keeping one by using return
grub_errno;
I was unaware 'grub_errno' was used so extensively. Thanks for the tip:
it definitely makes the logic cleaner.
}
I've followed all your recommendations (as far as possible). Here's the
code again.
~Peter Lustig
/* nthibr.c - tests whether an MS Windows system partition is hibernated */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2007,2008,2009,2011 Free Software Foundation, Inc.
*
* GRUB is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* GRUB is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
#include <grub/types.h>
#include <grub/mm.h>
#include <grub/disk.h>
#include <grub/file.h>
#include <grub/misc.h>
#include <grub/dl.h>
#include <grub/extcmd.h>
#include <grub/lib/arg.h>
#include <grub/err.h>
#include <grub/i18n.h>
GRUB_MOD_LICENSE("GPLv3+");
/* Define this 'empty' array to let the '-h' and '-u' switches be processed */
static const struct grub_arg_option options[] = {
{0, 0, 0, 0, 0, 0}
};
static grub_err_t
grub_cmd_nthibr (grub_extcmd_context_t ctxt __attribute__ ((unused)),
int argc, char **args)
{
char *partition_name = 0, *hibr_file_path = 0, hibr_file_magic[5];
grub_size_t name_length;
grub_ssize_t magic_size;
grub_disk_t partition;
grub_file_t hibr_file = 0;
/* Check argument count */
if (!argc)
return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("too few arguments"));
else if (argc > 1)
return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("too many arguments"));
/* Make copy of partition specifier, so it can be modified (if needed) */
name_length = grub_strlen (args[0]);
partition_name = grub_zalloc (name_length + 3);
if (!partition_name)
goto exit;
grub_strcpy (partition_name, args[0]);
/* Ensure partition specifier start with a '(' */
if (partition_name[0] != '(')
{
grub_memmove (partition_name + 1, partition_name, name_length++);
partition_name[0] = '(';
}
/* Ensure partition specifier ends with a ')' */
if (partition_name[name_length - 1] != ')')
partition_name[(++name_length) - 1] = ')';
/* Check if partition actually exists */
partition_name[name_length - 1] = '\0';
partition = grub_disk_open (partition_name + 1);
if (!partition)
goto exit;
grub_disk_close (partition);
partition_name[name_length - 1] = ')';
/* Build path to 'hiberfil.sys' */
hibr_file_path = grub_malloc ((grub_strlen (partition_name)
+ grub_strlen ("/hiberfil.sys") + 1));
if (!hibr_file_path)
goto exit;
grub_strcpy (hibr_file_path, partition_name);
grub_strcat (hibr_file_path, "/hiberfil.sys");
/* Try to open 'hiberfil.sys' */
hibr_file = grub_file_open (hibr_file_path);
if (!hibr_file)
{
if (grub_errno == GRUB_ERR_FILE_NOT_FOUND)
grub_error (GRUB_ERR_FILE_NOT_FOUND, N_("'hiberfil.sys' not found"));
goto exit;
}
/* Try to read magic number of 'hiberfil.sys' */
magic_size = sizeof (hibr_file_magic) - 1;
grub_memset (hibr_file_magic, 0, sizeof (hibr_file_magic));
if (grub_file_read (hibr_file, hibr_file_magic, magic_size) < magic_size)
{
if (!grub_errno)
grub_error (GRUB_ERR_BAD_FILE_TYPE, N_("'hiberfil.sys' too small"));
goto exit;
}
/* Return SUCCESS if magic indicates file is active; else return FAILURE */
if (!grub_strncasecmp ("hibr", hibr_file_magic, magic_size))
grub_error (GRUB_ERR_NONE, "true");
else
grub_error (GRUB_ERR_TEST_FAILURE, "false");
exit:
/* Ensure unmanaged resources are cleaned up */
if (partition_name)
grub_free (partition_name);
if (hibr_file_path)
grub_free (hibr_file_path);
if (hibr_file)
grub_file_close (hibr_file);
return grub_errno;
}
static grub_extcmd_t cmd;
GRUB_MOD_INIT (nthibr)
{
cmd = grub_register_extcmd ("nthibr", grub_cmd_nthibr, 0,
N_("DEVICE"),
N_("Test whether an NT system partition "
"is hibernated."),
options);
}
GRUB_MOD_FINI (nthibr)
{
grub_unregister_extcmd (cmd);
}
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